1. Field of the Invention
The present invention relates to an electromagnetic transducer laminate and an electromagnetic transducer which are used, for example, for converting a magnetic signal into an electric signal, a thin film magnetic head, a magnetic head assembly and a magnetic reproducing apparatus which magnetically reproduce information by using the electromagnetic transducer, and a method of manufacturing the electromagnetic transducer.
2. Description of the Related Art
In recent years, hard disk drives which magnetically record and reproduce information by using, for example, hard disks have been in widespread use as information recording/reproducing apparatuses. In the development of the hard disk drives, an improvement in performance of a thin film magnetic head has been sought in accordance with an increase in the areal density of a hard disk. The thin film magnetic head comprises, for example, an MR device which performs a reproducing process by using a magnetoresistive (MR) effect as a device for magnetic reproduction.
One of problems which arise in the development of the hard disk is that when the size of the MR device is reduced in accordance with an improvement in the areal density of the hard disk, a reproduction output declines resulting from a reduction in the physical size of the MR device. As a factor which causes a decline in the reproduction output, in addition to a reduction in the size of the MR device, for example, in a free layer functioning as a main part for detecting a signal magnetic field in the MR device, a discontinuous movement of a magnetic domain wall causes Barkhausen noise, so sensitivity of detecting the signal magnetic field by the free layer relatively declines. Therefore, in order to secure the reproduction output, it is necessary to eliminate the magnetic domain wall by bringing the free layer into a single magnetic domain state.
However, in a conventional hard disk drive, measures to control the magnetic domain of the free layer are not sufficient, so when the size of the MR device is reduced, it is difficult to obtain a sufficient reproduction output.